The next generation communication system, also known as the 4th generation (4G) communication systems, is a system for providing high-capacity data not only at high speed, but also with various Qualities of Service (QoS).
In particular, one of very important requirements in the 4G communication system is to implement a self-configurable wireless network. Herein, the self-configurable wireless network refers to a wireless network that can be configured not only in an autonomous manner, but also a distributive manner without the control of a central control system to provide mobile communication services.
In order to implement the self-configurable wireless communication network required in the 4G communication system, a multi-hop relay scheme may be applied. The multi-hop relay scheme refers to a scheme for transmitting data in a multi-hop manner by using Relay Stations (RS). When the multi-hop relay scheme is applied to the 4G communication system, it is possible to configure a wireless network capable of actively coping with changes in wireless environments, and to more efficiently operate the wireless network.
However, since a communication system employing the multi-hop relay scheme generally uses a frame that includes a Transmit/receive Transition Gap (TTG) and a Receive/transmit Transition Gap (RTG) and includes both a preamble for an RS and a preamble for a Mobile Station (MS), there is a problem in that time-frequency resources have reduced efficiency.
Herein, the TTG/RTG refers to a time gap for distinguishing between an interval during which data is transmitted from a Base Station (BS) to an RS and an interval during which data is transmitted from the RS to an MS. Also, the preamble for an RS refers to a signal for synchronization between a BS and an RS or between an RS and an RS, and the preamble for an MS refers to a signal for synchronization between a BS and an MS or between an RS and an MS.
In addition, there is another problem in that since the location of the preamble for an RS is fixed, the ratio between a frame section corresponding to a backhaul link and a frame section corresponding to an access link cannot be adaptively changed, and the ratio of the frame section corresponding to the backhaul link within the frame cannot increase above a certain level.
Herein, the backhaul link refers to a link between an RS and a BS or between an RS and an RS within the frame, and the access link refers to a link between an RS and an MS or between a BS and an MS.
Therefore, there is an urgent need for a frame structure that makes it possible to efficiently use time-frequency resources, instead of the conventional frame structure in which it is impossible to efficiently use time-frequency resources.